Speed: We’ve moved to a new infrastructure that makes every page faster. This new platform will enable us to keep up with traffic growth while ensuring Delicious is responsive and reliable. You may not have noticed, but the old back-end was getting creaky under the load of five million users.

Search: We’ve completely overhauled our search engine to make it faster and more powerful. Searches used to take ages to return results; now they’re very quick. The new search engine is also smarter, and more social: you can search within one of your tags, another user’s public bookmarks, or your social network. Now it’s easier to take advantage of the expertise and interests of your friends, not to mention the Delicious community at large.

Design: Finally, we’ve updated the user interface to improve usability and add a few often-requested features (such as selectable detail levels and alphabetical sorting of bookmarks). Our goal has been to keep the new design similar in spirit to the old one, so all of you veterans should be able to jump in without any confusion. At the same time, we’re hoping that newcomers to Delicious will find it easier to learn. Check out the What’s New page for an overview of the changes, or watch this animation that sums it up nicely:

And the movie that says it all:

UPDATE: earlier I predicted that a lot of users wouldn’t be able to log in again after being logged out by Del.icio.us when they moved to Delicious.com. There are a few complaints from people who can’t find their password in the Support Forums. Ironically the link to ‘Forgot your password’ leads to a ‘Sorry, Forbidden. You don’t have permission to access this URL on this server’ page at Yahoo. Try it yourself.

UPDATE 2: after thinking about that URL for a while I figured it out. This DOES work: https://secure.delicious.com/reverify. Took me 1 minute to find a fix. Wonder how long it will take Delicious…